JP2018188997A - Steam turbine plant, assembly method of the same and steam supply piping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam turbine plant capable of efficiently cooling a plurality of turbines with a simple cooling system and improving a plant efficiency.SOLUTION: A steam turbine plant includes a high pressure turbine 1 which is driven by steam introduced from a main steam inlet part 2 and a middle pressure turbine 6 which is driven by utilizing the steam exhausted from the high pressure turbine 1. The high pressure turbine 1 has an inlet cooling structure that cools a main steam inlet part 2 by circulating cooling steam. A steam supply piping 30 for supplying the cooling steam after cooling the main steam inlet part 2 to the middle pressure turbine 6 with an inlet cooling structure is provided between the high pressure turbine 1 and the middle pressure turbine 6. The middle pressure turbine 6 has a rotor cooling structure that cools a rotor by circulating the cooling steam supplied from the steam supply piping 30.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a steam turbine plant, an assembling method thereof, and an air supply pipe.

  In recent years, in a steam turbine plant, an increase in steam temperature for improving plant efficiency has been studied. When the steam temperature is increased, the thermal stress applied to the components of the steam turbine increases, so that it is necessary to improve the steam turbine to improve heat resistance.

  In a steam turbine in which high-temperature steam is used, the casing structure may have a double structure of an outer casing and an inner casing, and a structure in which steam can flow through the gap between the outer casing and the inner casing. Further, in the steam turbine having the structure as described above, the steam inlet portion has a double pipe structure of the outer pipe and the inner pipe, and the steam flowing through the gap between the outer casing and the inner casing is passed through the gap between the outer pipe and the inner pipe. There is also known a technique for cooling the inlet portion by circulating it.

JP 2006-307280 A JP 2010-255542 A

  FIG. 14 is a system diagram showing an example of a general steam turbine plant provided with a steam inlet having a double pipe structure as described above. In the example shown in FIG. 14, the cooling steam system 3 for circulating the cooling steam after cooling the main steam inlet 2 of the high-pressure turbine 1 is connected to the intermediate pressure turbine extraction system 4, and the intermediate pressure turbine extraction system 4 is The feed water heater 5 is connected. In addition, steam extracted from the high-pressure turbine 1 by the high-pressure turbine extraction system 7 is used as cooling steam for rotor cooling of the intermediate pressure turbine 6. As is apparent from these configurations, the system around the turbine of such a steam turbine plant is more complicated than a steam turbine plant that does not have a cooling system at the steam inlet.

  The cooling steam after cooling the main steam inlet 2 of the high-pressure turbine 1 and the cooling steam extracted from the high-pressure turbine 1 for cooling the rotor of the intermediate-pressure turbine 6 are used for driving the intermediate-pressure turbine. Not. Therefore, there is room for improvement in improving plant efficiency.

  The present invention has been made in view of the above circumstances, a steam turbine plant capable of efficiently cooling a plurality of turbines with a simple cooling system, and improving the plant efficiency, its assembling method, and air supply The purpose is to provide piping.

  A steam turbine plant according to an embodiment includes a first turbine driven by steam introduced from a main steam inlet, and a second turbine driven using steam exhausted from the first turbine. Prepare. The first turbine has an inlet cooling structure that cools the main steam inlet by circulating cooling steam, and the main cooling inlet is provided between the first turbine and the second turbine by the inlet cooling structure. An air supply pipe for supplying the cooling steam after cooling the steam inlet to the second turbine is provided. The second turbine has a rotor cooling structure that cools the rotor by circulating cooling steam supplied from the air supply pipe.

  The steam turbine plant assembly method according to the embodiment includes a first turbine driven by steam introduced from a main steam inlet, and a first turbine driven by using steam exhausted from the first turbine. 2 turbines, wherein the first turbine has an inlet cooling structure for cooling the main steam inlet by circulating cooling steam, and the second turbine distributes cooling steam supplied from the outside. This is a method for assembling a steam turbine plant having a rotor cooling structure for cooling the rotor. The method includes a step of providing an air supply pipe between the first turbine and the second turbine for supplying cooling steam after cooling the main steam inlet portion to the rotor cooling structure with the inlet cooling structure. It has.

  The air supply pipe according to the embodiment includes a first turbine driven by steam introduced from a main steam inlet, and a second turbine driven using steam exhausted from the first turbine. The air supply pipe provided between the two. The first turbine is provided with an inlet cooling structure for cooling the main steam inlet by circulating cooling steam, and the second turbine is provided with a rotor by circulating cooling steam supplied from the outside. A rotor cooling structure for cooling is provided, and the air supply pipe is configured to supply cooling steam after cooling the main steam inlet portion with the inlet cooling structure to the rotor cooling structure.

  According to the present invention, a plurality of turbines can be efficiently cooled with a simple cooling system, and plant efficiency can be improved.

1 is a system diagram of a steam turbine plant according to a first embodiment. It is the schematic of an example of the inlet_port | entrance cooling structure in the high pressure turbine of the steam turbine plant shown in FIG. It is the schematic of an example of the rotor cooling structure in the intermediate pressure turbine of the steam turbine plant shown in FIG. It is a systematic diagram of the steam turbine plant by 2nd Embodiment. It is a systematic diagram of the steam turbine plant by 3rd Embodiment. It is a systematic diagram of the steam turbine plant by 4th Embodiment. It is a systematic diagram of the steam turbine plant by 5th Embodiment. It is a systematic diagram of the steam turbine plant by 6th Embodiment. It is a systematic diagram of the steam turbine plant by 7th Embodiment. It is a systematic diagram of the steam turbine plant by 8th Embodiment. It is a systematic diagram of the steam turbine plant by 9th Embodiment. It is a systematic diagram of the steam turbine plant by 10th Embodiment. It is a systematic diagram of the steam turbine plant by 11th Embodiment. It is a distribution diagram showing an example of a general steam turbine plant.

  Embodiments will be described below in detail with reference to the accompanying drawings. Of the components in the following embodiments, the same components as those of the general steam turbine plant shown in FIG. 14 are denoted by the same reference numerals.

(First embodiment)
FIG. 1 is a system diagram of a steam turbine plant 100 according to the first embodiment. FIG. 1 shows a high-pressure turbine 1, a main steam inlet 2, an air supply pipe 30, and an intermediate-pressure turbine 6 that constitute a steam turbine plant 100.

  The high-pressure turbine 1 is a turbine driven by a steam MS1 (hereinafter referred to as main steam MS1) introduced from the main steam inlet 2, and the intermediate-pressure turbine 6 is a steam MS2 (hereinafter referred to as main steam) exhausted from the high-pressure turbine 1. It is a turbine driven using steam MS2). The high-pressure turbine 1 has an inlet cooling structure 20 that cools the main steam inlet 2 by circulating the cooling steam CS (see FIG. 2). Between the high-pressure turbine 1 and the intermediate-pressure turbine 6, An air supply pipe 30 is provided. The air supply pipe 30 connects the high-pressure turbine 1 and the intermediate-pressure turbine 6 in order to supply the intermediate-pressure turbine 6 with the cooling steam CS after the main steam inlet 2 is cooled by the inlet cooling structure 20.

  The intermediate pressure turbine 6 has a rotor cooling structure 60 that cools the rotor 6A by circulating the cooling steam CS supplied from the air supply pipe 30 (see FIG. 3). In the present embodiment and each embodiment described below, the high-pressure turbine 1 corresponds to the first turbine, and the intermediate-pressure turbine 6 corresponds to the second turbine.

  FIG. 2 is a schematic diagram illustrating an example of the inlet cooling structure 20 configured in the high-pressure turbine 1. As shown in FIG. 2, the main steam inlet portion 2 has a double pipe structure, and has an inner pipe 2A through which the main steam MS1 flows and an outer pipe 2B that covers the outside of the inner pipe 2A. In the inlet cooling structure 20 in the present embodiment, the gap 2C formed between the inner pipe 2A and the outer pipe 2B, and the main steam MS1 after flowing out of the inner pipe 2A and expanding, are used as cooling steam. An extraction flow path 2D that extracts air as CS and supplies it to the gap 2C. Since the cooling steam CS extracted by the extraction flow path 2D flows out of the inner pipe 2A and expands, its temperature is lowered. Such cooling steam CS flows through the gap 2C, whereby the main steam inlet 2 is cooled. Here, as shown in FIG. 2, the air supply pipe 30 is connected to the gap portion 2C so as to extract air from the gap portion 2C, whereby the cooling steam CS after cooling the main steam inlet portion 2 has an intermediate pressure. It will be supplied to the turbine 6.

  The extraction channel 2D in the present embodiment is configured to extract the main steam MS1 exhausted from the final stage of the high-pressure turbine 1, but the configuration of the extraction channel 2D is not particularly limited. For example, as shown by a two-dot chain line in FIG. 2, the extraction flow path 2D may extract the main steam MS1 from the middle stage of the high-pressure turbine 1 or a part of the main steam MS1 flowing out from the inner pipe 2A. May be extracted without sending to the paragraph side.

  On the other hand, FIG. 3 is a schematic diagram illustrating an example of a rotor cooling structure 60 configured in the intermediate pressure turbine 6. As shown in FIG. 3, the rotor cooling structure 60 in the present embodiment includes a flow path 60 </ b> A that guides the cooling steam CS flowing out from the air supply pipe 30 to the disk 61 of the first stage blade, and the movement of each stage. The axial passages 61A, 62A, 63A,... Formed in the wing disks 61, 62, 63,... It is formed with the nozzle diaphragm inner ring 6B1 of the stationary blade of the paragraph. In this rotor cooling structure 60, as indicated by the arrows in the figure, the cooling steam CS flowing out from the air supply pipe 30 is sent to the disk 61 of the first stage blade via the flow path 60A, and then penetrated. The holes 61A, 62A, 63A,. As a result, the rotor 6A is cooled.

  The steam turbine plant 100 as described above can be assembled, for example, by providing the air supply pipe 30 between the high pressure turbine 1 and the intermediate pressure turbine 6 after the high pressure turbine 1 and the intermediate pressure turbine 6 are installed. . Here, the air supply pipe 30 can be used even in a plant that has already been delivered, which is not supposed to be provided with the air supply pipe 30 at the time of delivery. Therefore, the high-pressure turbine 1 and the intermediate-pressure turbine 6 in the drawing may be existing turbines.

  The operation of the present embodiment will be described with reference to FIG. 1. First, the main steam MS 1 is generated by being heated by a boiler (not shown) and supplied from the main steam inlet 2 into the high-pressure turbine 1. Thereafter, the main steam MS1 passes through each stage in the high-pressure turbine 1, thereby driving the rotor of the high-pressure turbine 1. Thereafter, a part of the main steam MS1 is exhausted as main steam MS2 sent to the intermediate pressure turbine 6, and is supplied to the intermediate pressure turbine 6 after heating. On the other hand, the other part of the main steam MS1 reaches the gap 2C through the extraction flow path 2D of the inlet cooling structure 20 as the cooling steam CS, and cools the main steam inlet 2. Then, the cooling steam CS passes through the air supply pipe 30 and reaches the rotor cooling structure 60 of the intermediate pressure turbine 6 to cool the rotor 6A. Thereafter, in this example, the cooling steam CS joins the exhaust of the intermediate pressure turbine 6 and is exhausted.

  In such a steam turbine plant 100, the cooling steam CS after cooling the main steam inlet 2 of the high-pressure turbine 1 is reused for cooling the intermediate pressure turbine 6 by the air supply pipe 30, so that the cooling steam CS can be cooled. The piping system can be reduced as compared with the general configuration shown in FIG. Further, since the cooling steam CS after cooling the main steam inlet 2 of the high pressure turbine 1 is also used for cooling the intermediate pressure turbine 6, the main steam MS2 used for driving the intermediate pressure turbine 6 is increased. It is also possible to make it.

  Therefore, a plurality of turbines can be efficiently cooled with a simple cooling system, and the plant efficiency can be improved.

(Second Embodiment)
Next, a second embodiment will be described. Of the constituent parts in the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 4, the present embodiment is different from the first embodiment in that an orifice 8 is provided at a midway position of the air supply pipe 30. The orifice 8 is provided for adjusting the flow rate of the cooling steam CS from the upstream side and sending it to the downstream side.

  According to the present embodiment, the flow rate of the cooling steam CS flowing through the air supply pipe 30 can be restricted by the orifice 8. This prevents the cooling steam CS from flowing excessively to the air supply pipe 30, and the cooling steam CS flowing through the air supply pipe 30 is necessary for cooling the main steam inlet 2 and the rotor 6 </ b> A of the intermediate pressure turbine 6. It is possible to avoid the flow exceeding the maximum flow rate.

(Third embodiment)
Next, a third embodiment will be described. Of the components in the present embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 5, the present embodiment is different from the first embodiment in that a control valve 9 is provided in the middle position of the air supply pipe 30. The regulating valve 9 is configured to regulate the flow rate of the cooling steam CS from the upstream side and send it to the downstream side according to the opening degree.

  According to the present embodiment, the flow rate of the cooling steam CS flowing through the air supply pipe 30 can be adjusted by the control valve 9. Thus, when the flow rate of the cooling steam CS flowing through the air supply pipe 30 is excessive for cooling the main steam inlet portion 2 and the rotor 6A of the intermediate pressure turbine 6, only the necessary flow rate is reduced to the main steam inlet portion 2 and the middle The pressure turbine 6 can be supplied.

(Fourth embodiment)
Next, a fourth embodiment will be described. Of the constituent parts in this embodiment, the same parts as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 6, in the present embodiment, the three-way valve 10 is provided in the air supply pipe 30. One outlet 10D1 of the two outlets 10D1 and 10D2 of the three-way valve 10 is connected to the downstream portion 30D of the air supply pipe 30 arranged on the downstream side of the three-way valve 10, and the other outlet 10D2 is connected to the branch pipe 31. Is connected to the condenser 11. When the cooling steam CS is sent from the other outlet 10D2 to the condenser 11 according to the switching of the three-way valve 10, in this embodiment, the cooling steam CS is condensed and mixed into the condensate of the condenser 11. The The above points are different from the first embodiment.

  According to the present embodiment, the three-way valve 10 can switch between an operation for circulating the cooling steam CS flowing through the air supply pipe 30 to the intermediate pressure turbine 6 and an operation for not circulating it. The outlet 10D2 of the three-way valve 10 that is not connected to the intermediate pressure turbine 6 is connected to the condenser 11 via the branch pipe 31, and the cooling steam CS that has cooled the main steam inlet 2 is supplied to the condenser 11. It becomes possible to distribute. Thereby, when cooling of the rotor 6A of the intermediate pressure turbine 6 is unnecessary, the supply of the cooling steam CS to the intermediate pressure turbine 6 can be stopped without impairing the cooling of the main steam inlet portion 2.

(Fifth embodiment)
Next, a fifth embodiment will be described. Of the components in the present embodiment, the same components as those in the first to fourth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 7, in the present embodiment, the three-way valve 10 is provided in the air supply pipe 30. One outlet 10D1 of the two outlets 10D1 and 10D2 of the three-way valve 10 is connected to the downstream portion 30D of the air supply pipe 30 arranged on the downstream side of the three-way valve 10, and the other outlet 10D2 is connected to the branch pipe 31. Is connected to the feed water heater 5. When the cooling steam CS is sent from the other outlet 10D2 to the feed water heater 5 according to the switching of the three-way valve 10, in this embodiment, the cooling steam CS is used as heating steam in the feed water heater 5. . The above points are different from the first embodiment.

  According to the present embodiment, the three-way valve 10 can switch between an operation for circulating the cooling steam CS flowing through the air supply pipe 30 to the intermediate pressure turbine 6 and an operation for not circulating it. Then, the outlet 10D2 of the three-way valve 10 that is not connected to the intermediate pressure turbine 6 is connected to the feed water heater 5 via the branch pipe 31, and the cooling steam CS that has cooled the main steam inlet 2 is supplied to the feed water heater 5. It becomes possible to distribute. Thereby, when cooling of the rotor 6A of the intermediate pressure turbine 6 is unnecessary, the supply of the cooling steam CS to the intermediate pressure turbine 6 can be stopped without impairing the cooling of the main steam inlet portion 2. Moreover, the cooling steam CS which cooled the main steam inlet part 2 can also be utilized for heating of feed water.

(Sixth embodiment)
Next, a sixth embodiment will be described. Of the components in the present embodiment, the same components as those in the first to fifth embodiments are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 8, the present embodiment is different from the first embodiment in that the air supply pipe 30 is provided so as to pass through the condenser 11 and is cooled by the condenser 11. . A part of the air supply pipe 30 is arranged in the internal space of the condenser 11, and the part is cooled by steam or a cooling pipe in the internal space of the condenser 11.

  According to the present embodiment, the air supply pipe 30 is connected to the intermediate pressure turbine 6 after passing through the condenser 11. Thus, when the air supply pipe 30 passes through the condenser 11, the cooling steam CS flowing through the inside thereof is cooled, and the low-temperature cooling steam CS can be supplied to the intermediate pressure turbine 6.

(Seventh embodiment)
Next, a seventh embodiment will be described. Of the components in the present embodiment, the same components as those in the first to sixth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 9, the present embodiment is different from the first embodiment in that the air supply pipe 30 is provided so as to pass through the cooler 12 and is cooled by the cooler 12. A part of the air supply pipe 30 is brought into contact with or close to a cooling part (not shown) of the cooler 12 so that the part is cooled by the cooling part. The cooler 12 is, for example, an oil cooler for cooling the bearings of the generator, and is a device intended to cool a portion different from the cooling of the cooling steam CS or the steam.

  According to the present embodiment, the air supply pipe 30 is connected to the intermediate pressure turbine 6 after passing through the cooler 12. Thus, when the air supply pipe 30 passes through the cooler 12, the cooling steam CS flowing through the inside thereof is cooled, and the low-temperature cooling steam CS can be supplied to the intermediate pressure turbine 6.

(Eighth embodiment)
Next, an eighth embodiment will be described. Of the components in the present embodiment, the same components as those in the first to seventh embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 10, in the present embodiment, a gate valve 13 is provided in the air supply pipe 30. A branch pipe 31 connected to the condenser 11 is connected to an upstream portion 30U of the air supply pipe 30 arranged on the upstream side of the gate valve 13. When the cooling steam CS is sent from the branch pipe 31 to the condenser 11 in accordance with the switching of the gate valve 13, in the present embodiment, the cooling steam CS is condensed and mixed into the condensate of the condenser 11. . The above points are different from the first embodiment.

  According to the present embodiment, the gate valve 13 can be switched between an operation for circulating the cooling steam CS flowing through the air supply pipe 30 to the intermediate pressure turbine 6 and an operation for not circulating it. And since it has the system | strain connected to the condenser 11 upstream from the gate valve 13, since the flow path of the cooling steam CS is ensured, the cooling steam CS which cooled the main steam inlet part 2 is used as the condenser 11. It becomes possible to distribute to. Thereby, when the cooling of the rotor 6A of the intermediate pressure turbine 6 is unnecessary, the supply of the cooling steam CS to the intermediate pressure turbine 6 can be stopped without impairing the cooling of the main steam inlet 2.

(Ninth embodiment)
Next, a ninth embodiment will be described. Of the constituent parts in the present embodiment, the same parts as those in the first to eighth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 11, in the present embodiment, a gate valve 13 is provided in the air supply pipe 30. A branch pipe 31 connected to the feed water heater 5 is connected to the upstream portion 30U of the air supply pipe 30 arranged on the upstream side of the gate valve 13. When the cooling steam CS is sent from the branch pipe 31 to the feed water heater 5 in accordance with the switching of the gate valve 13, the cooling steam CS is used as heating steam in the feed water heater 5 in the present embodiment. The above points are different from the first embodiment.

  According to the present embodiment, the gate valve 13 can be switched between an operation for circulating the cooling steam CS flowing through the air supply pipe 30 to the intermediate pressure turbine 6 and an operation for not circulating it. And since it has the system | strain connected to the feed water heater 5 upstream from the gate valve 13, since the flow path of the cooling steam CS is ensured, the cooling steam CS which cooled the main steam inlet part 2 is supplied to the feed water heater 5. It becomes possible to distribute to. Thereby, when the cooling of the rotor 6A of the intermediate pressure turbine 6 is unnecessary, the supply of the cooling steam CS to the intermediate pressure turbine 6 can be stopped without impairing the cooling of the main steam inlet 2. Moreover, the cooling steam CS which cooled the main steam inlet part 2 can also be utilized for heating of feed water.

(Tenth embodiment)
Next, a tenth embodiment will be described. Of the components in the present embodiment, the same components as those in the first to ninth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 12, in the present embodiment, the adjustment valve 9 is provided in the air supply pipe 30. A branch pipe 31 connected to the condenser 11 is connected to the upstream portion 30U of the air supply pipe 30 arranged on the upstream side of the control valve 9. The control valve 9 can adjust the flow rate of the cooling steam CS supplied to the intermediate pressure turbine 6 and the flow rate of the cooling steam CS supplied to the condenser 11 according to the opening degree. When the cooling steam CS is sent from the branch pipe 31 to the condenser 11 according to the opening of the control valve 9, in this embodiment, the cooling steam CS is condensed and mixed into the condensate of the condenser 11. The The above points are different from the first embodiment.

  According to the present embodiment, the flow rate of the cooling steam CS flowing through the air supply pipe 30 can be adjusted by the control valve 9. And since it has the system | strain connected to the condenser 11 upstream from the control valve 9, it can distribute | circulate the cooling steam CS which may become excessive in cooling of the rotor 6A of the intermediate pressure turbine 6 to the condenser 11. It becomes possible. As a result, when the cooling steam CS that flows through the air supply pipe 30 and is supplied to the intermediate pressure turbine 6 can be excessive in cooling the rotor 6A, the cooling steam CS is reduced without impairing the cooling of the main steam inlet 2. Only a flow rate required for cooling the rotor 6A can be supplied to the intermediate pressure turbine 6.

(Eleventh embodiment)
Next, an eleventh embodiment will be described. Of the components in the present embodiment, the same components as those in the first to tenth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 13, in the present embodiment, the adjustment valve 9 is provided in the air supply pipe 30. A branch pipe 31 connected to the feed water heater 5 is connected to the upstream portion 30U of the air supply pipe 30 arranged on the upstream side of the control valve 9. The control valve 9 can adjust the flow rate of the cooling steam CS supplied to the intermediate pressure turbine 6 and the flow rate of the cooling steam CS supplied to the feed water heater 5 according to the opening degree. When the cooling steam CS is sent from the branch pipe 31 to the feed water heater 5 according to the opening of the control valve 9, the cooling steam CS is used as heating steam in the feed water heater 5 in the present embodiment. . The above points are different from the first embodiment.

  According to the present embodiment, the flow rate of the cooling steam CS flowing through the air supply pipe 30 can be adjusted by the control valve 9. And since it has the system | strain connected to the feed water heater 5 upstream from the control valve 9, it can distribute | circulate the cooling steam CS which may become excess in cooling of the rotor 6A of the intermediate pressure turbine 6 to the feed water heater 5. It becomes possible. As a result, when the cooling steam CS that flows through the air supply pipe 30 and is supplied to the intermediate pressure turbine 6 can be excessive in cooling the rotor 6A, the cooling steam CS is reduced without impairing the cooling of the main steam inlet 2. Only a flow rate required for cooling the rotor 6A can be supplied to the intermediate pressure turbine 6. Moreover, the cooling steam CS which cooled the main steam inlet part 2 can also be utilized for heating of feed water.

  As mentioned above, although each embodiment was described, each said embodiment was shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, the above-described air supply pipe 30 can be applied between an ultrahigh-pressure turbine and a high-pressure turbine, or between an intermediate-pressure turbine and a low-pressure turbine. In addition, the air supply pipe 30 may be provided with two or more members of the orifice 8, the control valve 9, the three-way valve 10, and the gate valve 13. The air supply pipe 30 may be arranged so as to pass through the condenser 11 and the cooler 12 and be cooled from both.

DESCRIPTION OF SYMBOLS 1 ... High pressure turbine, 2 ... Main steam inlet part, 2A ... Inner pipe, 2B ... Outer pipe, 2C ... Gap part, 2D ... Extraction flow path, 3 ... Cooling steam system, 4 ... Medium pressure turbine extraction system, 5 ... Supply water Heater, 6 ... Medium pressure turbine, 6A ... Rotor, 6B1 ... Nozzle diaphragm inner ring, 7 ... High pressure turbine bleed system, 8 ... Orifice, 9 ... Control valve, 10 ... Three-way valve, 10D1, 10D2 ... Outlet, 11 ... Condensate 12 ... cooler, 13 ... gate valve, 20 ... inlet cooling structure, 30 ... air supply piping, 30D ... downstream portion, 30U ... upstream portion, 31 ... branch piping, 60 ... rotor cooling structure, 60A ... flow path, 61, 62, 63 ... disk, 61A, 62A, 63A ... through hole, 100 ... steam turbine plant

Claims (7)

A first turbine driven by steam introduced from a main steam inlet;
A second turbine driven using steam exhausted from the first turbine, the first turbine having an inlet cooling structure for cooling the main steam inlet by circulating cooling steam. And
Between the first turbine and the second turbine, an air supply pipe for supplying cooling steam after cooling the main steam inlet portion with the inlet cooling structure to the second turbine is provided,
The said 2nd turbine is a steam turbine plant which has a rotor cooling structure which cools a rotor by distribute | circulating the cooling steam supplied from the said air supply piping.   The steam turbine plant according to claim 1, wherein at least one of an orifice, a control valve, a three-way valve, and a gate valve is provided in the air supply pipe. The air supply pipe is provided with the three-way valve,
One of the two outlets of the three-way valve is connected to a downstream portion of the air supply pipe disposed on the downstream side of the three-way valve, and the other of the two outlets of the three-way valve is a branch pipe. The steam turbine plant according to claim 2, wherein the steam turbine plant is connected to a condenser or a feed water heater. The air supply pipe is provided with the control valve or the gate valve,
The steam turbine plant according to claim 2, wherein a branch pipe connected to a condenser or a feed water heater is connected to an upstream portion of the air supply pipe arranged upstream of the control valve or the gate valve. .   The air supply pipe is provided so as to pass through at least one of a condenser and a cooler, and is cooled by at least one of the condenser and the cooler. The steam turbine plant according to claim 1. A first turbine driven by steam introduced from a main steam inlet, and a second turbine driven using steam exhausted from the first turbine, wherein the first turbine is cooling steam A steam turbine plant having an inlet cooling structure that cools the main steam inlet by circulating the steam, and the second turbine having a rotor cooling structure that cools the rotor by circulating cooling steam supplied from the outside The assembly method of
A step of providing an air supply pipe between the first turbine and the second turbine for supplying cooling steam after cooling the main steam inlet portion to the rotor cooling structure with the inlet cooling structure; A method for assembling a steam turbine plant. An air supply pipe provided between a first turbine driven by steam introduced from a main steam inlet and a second turbine driven using steam exhausted from the first turbine, ,
The first turbine is provided with an inlet cooling structure for cooling the main steam inlet by circulating cooling steam, and the second turbine is provided with a rotor by circulating cooling steam supplied from the outside. A rotor cooling structure for cooling is provided,
An air supply pipe for supplying cooling steam after cooling the main steam inlet portion to the rotor cooling structure with the inlet cooling structure.

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